Power gating may be used to reduce power leakage by a circuit in an electronic system, in which a power controller uses a switch to selectively connect the circuit to a power supply depending on whether the circuit is in operation. When the circuit is in operation, the power controller turns on the switch to connect the circuit to the power supply through the switch. When the circuit is turned off or in standby mode, the power controller turns off the switch to disconnect the circuit from the power supply. The circuit may comprise a memory, logic or another type of circuit. The switch may have a low resistance so that power dissipation across the switch is minimized when the circuit is connected to the power supply through the switch.
Power gating may cause a large current surge through the power supply when the switch is first turned on due to the low resistance of the switch and a large voltage difference between the power supply and the circuit when the switch is first turned on. The current surge may create a large IR voltage drop in the power supply because of power grid resistance and/or package inductance. This drop may cause other circuits connected to the power supply to lose their state, thus causing functionality failure.